/* * ah_decrypt.c : IPSec AH decrypt node * * Copyright (c) 2015 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <vnet/vnet.h> #include <vnet/api_errno.h> #include <vnet/ip/ip.h> #include <vnet/ipsec/ipsec.h> #include <vnet/ipsec/esp.h> #include <vnet/ipsec/ah.h> #define foreach_ah_decrypt_next \ _ (DROP, "error-drop") \ _ (IP4_INPUT, "ip4-input") \ _ (IP6_INPUT, "ip6-input") \ _ (IPSEC_GRE_INPUT, "ipsec-gre-input") #define _(v, s) AH_DECRYPT_NEXT_##v, typedef enum { foreach_ah_decrypt_next #undef _ AH_DECRYPT_N_NEXT, } ah_decrypt_next_t; #define foreach_ah_decrypt_error \ _ (RX_PKTS, "AH pkts received") \ _ (DECRYPTION_FAILED, "AH decryption failed") \ _ (INTEG_ERROR, "Integrity check failed") \ _ (REPLAY, "SA replayed packet") typedef enum { #define _(sym,str) AH_DECRYPT_ERROR_##sym, foreach_ah_decrypt_error #undef _ AH_DECRYPT_N_ERROR, } ah_decrypt_error_t; static char *ah_decrypt_error_strings[] = { #define _(sym,string) string, foreach_ah_decrypt_error #undef _ }; typedef struct { ipsec_integ_alg_t integ_alg; u32 seq_num; } ah_decrypt_trace_t; /* packet trace format function */ static u8 * format_ah_decrypt_trace (u8 * s, va_list * args) { CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *); CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *); ah_decrypt_trace_t *t = va_arg (*args, ah_decrypt_trace_t *); s = format (s, "ah: integrity %U seq-num %d", format_ipsec_integ_alg, t->integ_alg, t->seq_num); return s; } always_inline uword ah_decrypt_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame, int is_ip6) { u32 n_left_from, *from, next_index, *to_next; ipsec_main_t *im = &ipsec_main; ipsec_proto_main_t *em = &ipsec_proto_main; from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; int icv_size = 0; next_index = node->cached_next_index; while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 i_bi0; u32 next0; vlib_buffer_t *i_b0; ah_header_t *ah0; ipsec_sa_t *sa0; u32 sa_index0 = ~0; u32 seq; ip4_header_t *ih4 = 0, *oh4 = 0; ip6_header_t *ih6 = 0, *oh6 = 0; u8 ip_hdr_size = 0; u8 tos = 0; u8 ttl = 0; u32 ip_version_traffic_class_and_flow_label = 0; u8 hop_limit = 0; u8 nexthdr = 0; u8 icv_padding_len = 0; i_bi0 = from[0]; from += 1; n_left_from -= 1; n_left_to_next -= 1; next0 = AH_DECRYPT_NEXT_DROP; i_b0 = vlib_get_buffer (vm, i_bi0); to_next[0] = i_bi0; to_next += 1; ih4 = vlib_buffer_get_current (i_b0); ih6 = vlib_buffer_get_current (i_b0); sa_index0 = vnet_buffer (i_b0)->ipsec.sad_index; sa0 = pool_elt_at_index (im->sad, sa_index0); if (is_ip6) { ip6_ext_header_t *prev = NULL; ip6_ext_header_find_t (ih6, prev, ah0, IP_PROTOCOL_IPSEC_AH); ip_hdr_size = sizeof (ip6_header_t); ASSERT ((u8 *) ah0 - (u8 *) ih6 == ip_hdr_size); } else { ip_hdr_size = ip4_header_bytes (ih4); ah0 = (ah_header_t *) ((u8 *) ih4 + ip_hdr_size); } seq = clib_host_to_net_u32 (ah0->seq_no); /* anti-replay check */ if (sa0->use_anti_replay) { int rv = 0; if (PREDICT_TRUE (sa0->use_esn)) rv = esp_replay_check_esn (sa0, seq); else rv = esp_replay_check (sa0, seq); if (PREDICT_FALSE (rv)) { if (is_ip6) vlib_node_increment_counter (vm, ah6_decrypt_node.index, AH_DECRYPT_ERROR_REPLAY, 1); else vlib_node_increment_counter (vm, ah4_decrypt_node.index, AH_DECRYPT_ERROR_REPLAY, 1); goto trace; } } sa0->total_data_size += i_b0->current_length; icv_size = em->ipsec_proto_main_integ_algs[sa0->integ_alg].trunc_size; if (PREDICT_TRUE (sa0->integ_alg != IPSEC_INTEG_ALG_NONE)) { u8 sig[64]; u8 digest[64]; clib_memset (sig, 0, sizeof (sig)); clib_memset (digest, 0, sizeof (digest)); u8 *icv = ah0->auth_data; memcpy (digest, icv, icv_size); clib_memset (icv, 0, icv_size); if (is_ip6) { ip_version_traffic_class_and_flow_label = ih6->ip_version_traffic_class_and_flow_label; hop_limit = ih6->hop_limit; ih6->ip_version_traffic_class_and_flow_label = 0x60; ih6->hop_limit = 0; nexthdr = ah0->nexthdr; icv_padding_len = ah_calc_icv_padding_len (icv_size, 1 /* is_ipv6 */ ); } else { tos = ih4->tos; ttl = ih4->ttl; ih4->tos = 0; ih4->ttl = 0; ih4->checksum = 0; ih4->flags_and_fragment_offset = 0; icv_padding_len = ah_calc_icv_padding_len (icv_size, 0 /* is_ipv6 */ ); } hmac_calc (sa0->integ_alg, sa0->integ_key, sa0->integ_key_len, (u8 *) ih4, i_b0->current_length, sig, sa0->use_esn, sa0->seq_hi); if (PREDICT_FALSE (memcmp (digest, sig, icv_size))) { if (is_ip6) vlib_node_increment_counter (vm, ah6_decrypt_node.index, AH_DECRYPT_ERROR_INTEG_ERROR, 1); else vlib_node_increment_counter (vm, ah4_decrypt_node.index, AH_DECRYPT_ERROR_INTEG_ERROR, 1); goto trace; } if (PREDICT_TRUE (sa0->use_anti_replay)) { if (PREDICT_TRUE (sa0->use_esn)) esp_replay_advance_esn (sa0, seq); else esp_replay_advance (sa0, seq); } } vlib_buffer_advance (i_b0, ip_hdr_size + sizeof (ah_header_t) + icv_size + icv_padding_len); i_b0->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID; if (PREDICT_TRUE (sa0->is_tunnel)) { /* tunnel mode */ if (PREDICT_TRUE (ah0->nexthdr == IP_PROTOCOL_IP_IN_IP)) next0 = AH_DECRYPT_NEXT_IP4_INPUT; else if (ah0->nexthdr == IP_PROTOCOL_IPV6) next0 = AH_DECRYPT_NEXT_IP6_INPUT; else { if (is_ip6) vlib_node_increment_counter (vm, ah6_decrypt_node.index, AH_DECRYPT_ERROR_DECRYPTION_FAILED, 1); else vlib_node_increment_counter (vm, ah4_decrypt_node.index, AH_DECRYPT_ERROR_DECRYPTION_FAILED, 1); goto trace; } } else { /* transport mode */ if (is_ip6) { vlib_buffer_advance (i_b0, -sizeof (ip6_header_t)); oh6 = vlib_buffer_get_current (i_b0); memmove (oh6, ih6, sizeof (ip6_header_t)); next0 = AH_DECRYPT_NEXT_IP6_INPUT; oh6->protocol = nexthdr; oh6->hop_limit = hop_limit; oh6->ip_version_traffic_class_and_flow_label = ip_version_traffic_class_and_flow_label; oh6->payload_length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, i_b0) - sizeof (ip6_header_t)); } else { vlib_buffer_advance (i_b0, -sizeof (ip4_header_t)); oh4 = vlib_buffer_get_current (i_b0); memmove (oh4, ih4, sizeof (ip4_header_t)); next0 = AH_DECRYPT_NEXT_IP4_INPUT; oh4->ip_version_and_header_length = 0x45; oh4->fragment_id = 0; oh4->flags_and_fragment_offset = 0; oh4->protocol = ah0->nexthdr; oh4->length = clib_host_to_net_u16 (vlib_buffer_length_in_chain (vm, i_b0)); oh4->ttl = ttl; oh4->tos = tos; oh4->checksum = ip4_header_checksum (oh4); } } /* for IPSec-GRE tunnel next node is ipsec-gre-input */ if (PREDICT_FALSE ((vnet_buffer (i_b0)->ipsec.flags) & IPSEC_FLAG_IPSEC_GRE_TUNNEL)) next0 = AH_DECRYPT_NEXT_IPSEC_GRE_INPUT; vnet_buffer (i_b0)->sw_if_index[VLIB_TX] = (u32) ~ 0; trace: if (PREDICT_FALSE (i_b0->flags & VLIB_BUFFER_IS_TRACED)) { i_b0->flags |= VLIB_BUFFER_IS_TRACED; ah_decrypt_trace_t *tr = vlib_add_trace (vm, node, i_b0, sizeof (*tr)); tr->integ_alg = sa0->integ_alg; tr->seq_num = seq; } vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, i_bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } if (is_ip6) vlib_node_increment_counter (vm, ah6_decrypt_node.index, AH_DECRYPT_ERROR_RX_PKTS, from_frame->n_vectors); else vlib_node_increment_counter (vm, ah4_decrypt_node.index, AH_DECRYPT_ERROR_RX_PKTS, from_frame->n_vectors); return from_frame->n_vectors; } VLIB_NODE_FN (ah4_decrypt_node) (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return ah_decrypt_inline (vm, node, from_frame, 0 /* is_ip6 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (ah4_decrypt_node) = { .name = "ah4-decrypt", .vector_size = sizeof (u32), .format_trace = format_ah_decrypt_trace, .type = VLIB_NODE_TYPE_INTERNAL, .n_errors = ARRAY_LEN(ah_decrypt_error_strings), .error_strings = ah_decrypt_error_strings, .n_next_nodes = AH_DECRYPT_N_NEXT, .next_nodes = { #define _(s,n) [AH_DECRYPT_NEXT_##s] = n, foreach_ah_decrypt_next #undef _ }, }; /* *INDENT-ON* */ VLIB_NODE_FN (ah6_decrypt_node) (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return ah_decrypt_inline (vm, node, from_frame, 1 /* is_ip6 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (ah6_decrypt_node) = { .name = "ah6-decrypt", .vector_size = sizeof (u32), .format_trace = format_ah_decrypt_trace, .type = VLIB_NODE_TYPE_INTERNAL, .n_errors = ARRAY_LEN(ah_decrypt_error_strings), .error_strings = ah_decrypt_error_strings, .n_next_nodes = AH_DECRYPT_N_NEXT, .next_nodes = { #define _(s,n) [AH_DECRYPT_NEXT_##s] = n, foreach_ah_decrypt_next #undef _ }, }; /* *INDENT-ON* */ /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */